Open whispering gallery modes resonators

TL;DR

This paper introduces open whispering gallery mode resonators that reduce mode density and enable directional radiation, improving light extraction and spectral sparsity for photonics applications, with potential benefits for laser and optical communication technologies.

Contribution

The paper proposes open WGM resonators that address traditional limitations by decreasing mode density and facilitating directional emission, demonstrated through numerical simulations and optimized coupling designs.

Findings

Significant increase in intermode distance in 2D metallic and dielectric disk resonators.

Formation of sparse spectra in 3D dielectric OWGM resonators suitable for photonics.

Near-unity transmission achieved with a cylindrical Bragg microresonator coupled to a single-mode fiber.

Abstract

There are some issues with traditional whispering gallery mode (WGM) resonators like poor light extraction and a dense mode spectrum. In this paper we introduce a solution to these limitations by proposing open WGM (OWGM) resonators that effectively reduce the mode density and enable directional radiation through a connected waveguide at the expense of some lowering in Q-factor. Numerical simulations of two-dimensional metallic and dielectric disk resonators with holes reveal a significant increase in intermode distance. The study also extends to three-dimensional dielectric OWGM resonators, demonstrating the formation of sparse spectra suitable for photonics applications. Additionally, the design of a cylindrical Bragg microresonator connected to a single-mode fiber via an optimized topology-based connector achieves near-unity transmission and efficient coupling. This approach enhances the development of new photonic devices, addressing the limitations of traditional high Q-factor WGM resonators and offering potential advancements in laser technology and optical communications, where compactness and manufacturability are prioritized over ultra-high Q-factors.